Émilie Du Châtelet

Gabrielle Émilie Le Tonnelier de Breteuil, Marquise du Châtelet (; 17 December 1706 – 10 September 1749) was a French natural philosopher and mathematician from the early 1730s until her death due to complications during childbirth in 1749. Her most recognized achievement is her translation of and commentary on Isaac Newton's 1687 book ''Philosophiæ Naturalis Principia Mathematica'' containing basic laws of physics. The translation, published posthumously in 1756, is still considered the standard French translation. Her commentary includes a contribution to Newtonian mechanics—the postulate of an additional conservation law for total energy, of which kinetic energy of motion is one element. This led to her conceptualization of energy as such, and to derive its quantitative relationships to the mass and velocity of an object.

Her philosophical magnum opus, ''Institutions de Physique'' (Paris, 1740, first edition; ''Foundations of Physics''), circulated widely, generated heated debates, and was republished and translated into several other languages within two years of its original publication. She participated in the famous '' vis viva'' debate, concerning the best way to measure the force of a body and the best means of thinking about conservation principles. Posthumously, her ideas were heavily represented in the most famous text of the French Enlightenment, the '' Encyclopédie'' of Denis Diderot and Jean le Rond d'Alembert, first published shortly after du Châtelet's death. Numerous biographies, books and plays have been written about her life and work in the two centuries since her death. In the early 21st century, her life and ideas have generated renewed interest.

Émilie du Châtelet had, over many years, a relationship with the writer and philosopher Voltaire.

Contribution to philosophy

In addition to producing famous translations of works by authors such as Bernard Mandeville and Isaac Newton, Du Châtelet wrote a number of significant philosophical essays, letters and books that were well known in her time.

Because of her well-known collaboration and romantic involvement with Voltaire, which spanned much of her adult life, for generations Du Châtelet has been known as mistress and collaborator to her much better known intellectual companion. Her accomplishments and achievements have often been subsumed under his and, as a result, even today she is often mentioned only within the context of Voltaire's life and work during the period of the early French Enlightenment. The ideals of her works spread from the ideals of individual empowerment to issues of the social contract.

Recently, however, professional philosophers and historians have transformed the reception of Du Châtelet. Historical evidence indicates that Du Châtelet's work had a very significant influence on the philosophical and scientific conversations of the 1730s and 1740s – in fact, she was famous and respected by the greatest thinkers of her time. Francesco Algarotti styled the dialogue of ''Il Newtonianismo per le dame'' based on conversations he observed between Du Châtelet and Voltaire in Cirey.

Du Châtelet corresponded with renowned mathematicians such as Johann II Bernoulli and Leonhard Euler, early developers of calculus. She was also tutored by Bernoulli's prodigy students, Pierre Louis Moreau de Maupertuis and Alexis Claude Clairaut. Frederick the Great of Prussia, who re-founded the Academy of Sciences in Berlin, was her great admirer, and corresponded with both Voltaire and Du Châtelet regularly. He introduced Du Châtelet to Leibniz's philosophy by sending her the works of Christian Wolff, and Du Châtelet sent him a copy of her ''Institutions.''

Her works were published and republished in Paris, London, and Amsterdam; they were translated into German and Italian; and, they were discussed in the most important scholarly journals of the era, including the '' Memoires des Trévoux'', the ''Journal des Sçavans'', the '' Göttingische Zeitungen von gelehrten Sachen'', and others. Perhaps most intriguingly, many of her ideas were represented in various sections of the ''Encyclopédie'' of Diderot and D'Alembert, and some of the articles in the ''Encyclopédie'' are a direct copy of her work (this is an active area of current academic research - the latest research can be found a
Project Vox
a Duke University research initiative).

Biography

Early life

Émilie du Châtelet was born on 17 December 1706 in Paris, the only girl amongst six children. Three brothers lived to adulthood: René-Alexandre (b. 1698), Charles-Auguste (b. 1701), and Elisabeth-Théodore (b. 1710). Her eldest brother, René-Alexandre, died in 1720, and the next brother, Charles-Auguste, died in 1731. However, her younger brother, Elisabeth-Théodore, lived to a successful old age, becoming an abbot and eventually a bishop. Two other brothers died very young. Du Châtelet also had a half-sister, Michelle, who was born of her father and Anne Bellinzani, an intelligent woman who was interested in astronomy and married to an important Parisian official.

Her father was Louis Nicolas le Tonnelier de Breteuil, a member of the lesser nobility. At the time of Du Châtelet's birth, her father held the position of the Principal Secretary and Introducer of Ambassadors to King Louis XIV. He held a weekly ''salon'' on Thursdays, to which well-respected writers and scientists were invited. Her mother was Gabrielle Anne de Froullay, Baronne de Breteuil.

Early education

Du Châtelet's education has been the subject of much speculation, but nothing is known with certainty.Zinsser.

Among their acquaintances was Fontenelle, the perpetual secretary of the French Académie des Sciences. Du Châtelet's father Louis-Nicolas, recognizing her early brilliance, arranged for Fontenelle to visit and talk about astronomy with her when she was 10 years old. Du Châtelet's mother, Gabrielle-Anne de Froulay, was brought up in a convent, at the time the predominant educational institution available to French girls and women. While some sources believe her mother did not approve of her intelligent daughter, or of her husband's encouragement of Émilie's intellectual curiosity, there are also other indications that her mother not only approved of Du Châtelet's early education, but actually encouraged her to vigorously question stated fact.Zinsser (2006: 26–29)

In either case, such encouragement would have been seen as unusual for parents of their time and status. When she was small, her father arranged training for her in physical activities such as fencing and riding, and as she grew older, he brought tutors to the house for her. As a result, by the age of twelve she was fluent in Latin, Italian, Greek and German; she was later to publish translations into French of Greek and Latin plays and philosophy. She received education in mathematics, literature, and science.

Du Châtelet also liked to dance, was a passable performer on the harpsichord, sang opera, and was an amateur actress. As a teenager, short of money for books, she used her mathematical skills to devise highly successful strategies for gambling.

Marriage

On 12 June 1725, she married the Marquis Florent-Claude du Chastellet-Lomont.The ''Lomont'' suffix indicates the branch of the ''du Chastellet'' family; another such branch was the ''du Chastellet-Clemont''. Her marriage conferred the title of Marquise du Chastellet.The spelling ''Châtelet'' (replacing the ''s'' by a circumflex over the ''a'') was introduced by Voltaire, and has now become standard. () Like many marriages among the nobility, theirs was arranged. As a wedding gift, her husband was made governor of Semur-en-Auxois in Burgundy by his father; the recently married couple moved there at the end of September 1725. Du Châtelet was eighteen at the time, her husband thirty-four.

Children

The Marquis Florent-Claude du Chastellet and Émilie du Châtelet had three children: Françoise-Gabrielle-Pauline (30 June 1726 – 1754, married in 1743 to Alfonso Carafa, Duca di Montenero), Louis Marie Florent (born 20 November 1727), and Victor-Esprit (born 11 April 1733).Zinsser, pp. 39 and 58. Victor-Esprit died as an infant in late summer 1734, likely the last Sunday in August.Zinsser, pp. 40 and 93. On 4 September 1749 Émilie du Châtelet gave birth to Stanislas-Adélaïde du Châtelet (daughter of Jean François de Saint-Lambert). She died as a toddler in Lunéville on 6 May 1751.

Resumption of studies

After bearing three children, Émilie, Marquise du Châtelet, considered her marital responsibilities fulfilled and reached an agreement with her husband to live separate lives while still maintaining one household. In 1733, aged 26, Du Châtelet resumed her mathematical studies. Initially, she was tutored in algebra and calculus by Moreau de Maupertuis, a member of the Academy of Sciences; although mathematics was not his forte, he had received a solid education from Johann Bernoulli, who also taught Leonhard Euler. However by 1735 Du Châtelet had turned for her mathematical training to Alexis Clairaut, a mathematical prodigy known best for Clairaut's equation and Clairaut's theorem. Du Châtelet resourcefully sought some of France's best tutors and scholars to mentor her in mathematics. On one occasion at the Café Gradot, a place where men frequently gathered for intellectual discussion, she was politely ejected when she attempted to join one of her teachers. Undeterred, she returned and entered after having men's clothing made for herself.

Relationship with Voltaire

Du Châtelet may have met Voltaire in her childhood at one of her father's ''salons''; Voltaire himself dates their meeting to 1729, when he returned from his exile in London. However, their friendship developed from May 1733 when she re-entered society after the birth of her third child.

Du Châtelet invited Voltaire to live at her country house at Cirey in Haute-Marne